JPH0210059B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention is directed to a hybrid high-speed printing press in which a plate-making unit and a separate printing unit are integrated, in which a web consisting of an original plate that is being made is wound around a printing drum. This invention relates to a web tension adjustment method.

Conventional technology Conventionally, this type of adjustment method involves: (1) setting the drum rotation peripheral speed at no load to be higher than the web conveyance speed; and when winding the web, the drive transmission unit that transmits the driving force to the printing drum (2) Measuring the winding speed and conveyance speed separately and matching the two speeds accurately. I was worried.

However, in the case of (1), a separate torque limiter must be provided in the drive transmission section, which not only complicates the structure of the drive transmission section, but also
The printing drum is not only used to wind up the web; it also has to perform printing.
The drawback is that the torque limiter must be moved in and out of position at a constant phase, making the structure even more complex. In addition, in (2), in order to accurately match both speeds, not only must the precision of each part be extremely high, but also precise control is required, which requires extremely expensive Further, when the conveying speed changes, it is extremely difficult to accurately increase or decrease the winding speed, and accurate synchronization is difficult to achieve.

Object The object of the present invention is to provide an adjustment method that eliminates the drawbacks of the conventional adjustment methods as described above, does not require a complicated adjustment method, and automatically maintains the tension of a web within a predetermined value. is to provide.

Configuration The configuration of the present invention will be described with reference to embodiments shown in the drawings.

In FIG. 1, 1 indicates a web consisting of an original plate sent out by a plate-making unit (not shown), with upper and lower 1
The speed is controlled by the restraining member 2 consisting of a pair of pinching rollers.
V1, the printing drum 4 is sent in the direction of the arrow, is clamped and restrained by the conveying member 3 consisting of a pair of upper and lower clamping rollers, and is also held by the clamper 6 of the printing drum 4, which is stopped at the first speed V2 with a take-up speed of zero. Its tip is held and can be wound up. Due to this speed difference, in the middle between the conveying member 2 and the restraining member 3,
Since slack occurs in the web 1, a detection device roller 5 (not shown) is placed here to detect the amount of slack.

As the web 1 continues to be fed in this way, the amount of slack increases, and the detection roller 5, which was at the solid line position, descends to the chain line position.When the maximum amount of slack set in the main body of the detection device is reached in this way, the detection roller 5 The main body of the apparatus outputs a signal, which is transmitted to a drive member (not shown) of the print drum 4, and the drive member switches the winding speed of the print drum 4 to a second speed V3, which is higher than the conveyance speed V1.

As a result, the amount of slack in the web 1 gradually decreases, and the detection roller 5 rises accordingly. When the minimum amount of slack set in the main body of the detection device is reached, the drive member is activated by the signal transmitted from the main body of the detection device. 4 is again switched to the first speed V2 of zero.

In this way, when the web 1 reaches both the preset maximum and minimum slack amounts, the web 1 is continuously maintained within a predetermined range by automatically switching the take-up speed of the printing drum 4 and printed. It will be wound around the drum 4 with a constant tension. In this case, even if the conveyance speed V1 changes, the same thing will happen as long as it is within the range of V3>V1>V2. This relationship is shown in FIG. 2, where the relationship between the amount of slack and the feed speed is expressed in time series.

FIG. 3 shows an embodiment in which an ultrasonic sensor is used as the detection device, and 7 and 8 indicate an ultrasonic transmitter and a receiver, respectively, which function in the same way as the detection roller 5.

In the above explanation, the maximum and minimum values of the amount of deflection are used. In this case, the maximum value is a value that can avoid the risk of jamming, and the minimum value is a value that can avoid the risk of jamming. The respective values are set to prevent the web 1 from falling off from the clamp or being torn when it is excessively pulled due to the rotation of the printing drum 4.

A second off control mechanism may be provided which also stops the transport member when the print drum stops.

In any of the above embodiments, the restraining action of the restraining member 3 is to apply a brake to the roller shaft;
The roller shaft may be rotated by a low capacity motor in a direction opposite to the feed direction, or a frictional force may be created between the roller surface and the web surface.

Effects This invention is as described above, in which the winding speed of the printing drum is stopped at the first speed of zero, a slack is created between the restraining member and the conveying member, and the amount of slack in the slack portion is set. When the upper value is reached, the winding speed of the printing drum is set to a second speed higher than the conveyance speed by the conveying member, and when the same amount of slack reaches the lower value, the winding speed is set to a first speed of zero, Since the printing drum is rotated intermittently, the leading edge of the web can be rotated between the printing drum and the leading edge of the web, despite the difference in transport speed and take-up speed during rotation caused by the relationship between the printing drum and the plate-making section, which have different processing speeds. The web can be clamped accurately with a clamper, and since the amount of slack in the web only increases or decreases between the conveying member and the restraining member, torque fluctuations in the printing drum due to intermittent rotation are not transmitted to the plate-making section. The present invention has the effect that the plate-making process is carried out normally, and in order to achieve this effect, it is possible to automatically keep the web tension within a set value without installing a particularly complicated and highly accurate adjusting device. There is an effect that it can be done.

[Brief explanation of drawings]

Fig. 1 is a front view of the main parts of the embodiment used in the method of the present invention, Fig. 2 is a time series diagram showing the operation of the same as above, and Fig. 3 is a front view of the main parts of the embodiment used in the method of the present invention. FIG. 7 is a front view of main parts of another embodiment. 1... Web, 2... Conveying member, 3... Restraining member, 4... Printing drum, 5... Detection roller, 7,
8... Ultrasonic sensor.

Claims (1)

[Claims] 1. A restraining member that applies tension to the web in front of the printing drum when the web made of the original plate sent out by the plate making unit is wound up on the printing drum, and a conveyance member that continuously feeds the web to the restraining member. In a hybrid-type high-speed printing machine equipped with and a second speed faster than the conveying speed of the conveying member.
When the amount of slack in the slack portion is measured and it is detected that it has reached a predetermined value, the winding speed of the printing drum is changed to the first speed based on the detection signal. Alternatively, a web tension adjustment method characterized in that a predetermined amount of slack is maintained by automatically switching to a second speed.